The invention relates to a sampling system for collecting a liquid sample using at least one analytic auxiliary means. The invention further relates to a method for collecting a liquid sample. Such sampling systems and methods are used in particular in medical diagnostics in the hospital sector, in the home care sector or in a home-monitoring environment for determining the concentration of at least one analyte, for example, a metabolite such as blood glucose, in a bodily fluid.
Examining blood samples or other samples of bodily fluid, such as interstitial fluid, allows early and reliable detection of pathological states and the targeted and informed monitoring of body states in clinical diagnostics. Medical diagnostics generally require the collection of a sample of blood or interstitial fluid of the individual to be examined.
In order to obtain the sample, the skin, e.g., on the fingertips or ear lobe of the person to be examined, can be perforated using a sterile, pointed or sharp lancet so as to obtain a few microliters or less of blood for the analysis. This method is particularly suitable for the analysis of a sample which is performed directly after collecting the sample.
Lancets and so-called lancing devices which allow reproducible sample collection involving as little pain as possible are offered in particular in the sector of so-called “home monitoring,” that is to say where laymen themselves perform simple analyses of the blood or interstitial fluid, particularly for the periodic (a few times a day) collection of blood by diabetics for monitoring blood glucose concentration. Such lancets and equipment (lancing devices) are, for example, the subject matter of Publication No. WO 98/48695A1, U.S. Pat. No. 4,442,836, U.S. Pat. No. 5,554,166 or Publication No. WO 2006/013045A1.
These days, self-determination of blood sugar is a universally adopted method in diabetes monitoring. In the prior art, blood sugar equipment generally has analysis equipment into which a test element (test strip) is inserted. The test element is brought into contact with a drop of a sample which was previously collected from, for example, the fingertip using a lancing device.
Analysis equipment in which the sample to be analyzed is situated on a test field on a test element and, if need be, reacts with one or more reagents in the test field before it is analyzed, is often used for analyzing liquid samples, e.g., bodily fluids such as blood or urine. Optical, in particular photometric, and electrochemical evaluations of test elements are the most common methods for quickly determining the concentration of analytes in samples. Analysis systems with test elements for sample analysis are generally used in the field of analysis, environmental analysis and, particularly, in the field of medical diagnostics. Test elements evaluated by photometric or electrochemical means are particularly important in the field of blood glucose diagnostics from capillary blood.
There are different forms of test elements. By way of example, basically square slides, which have a multilayered test field situated in the center thereof are known. Diagnostic test elements with a strip-shaped design are referred to as test strips. The prior art comprehensively describes test elements, for example, in the documents Canadian Patent No. 2311496 A1; U.S. Pat. No. 5,846,837; U.S. Pat. No. 6,036,919 or Publication No. WO 97/02487.
Analysis tapes with a plurality of test fields which are wound up in a cassette and provided for use in analysis equipment are examples of multilayered test elements disclosed in the prior art. By way of example, German Patent No. DE 103 32 488 A1, German Patent No. DE 103 43 896 A1, European Patent No. EP 1 424 040 A1, Publication No. WO 2004/056269 A1 and U.S. Publication No. 2006/0002816 A1 describe such cassettes and analysis tapes.
The numerous system components (lancet, lancing device, test element and analysis equipment) require a lot of space and are relatively complicated to handle. Systems with a higher degree of integration and thus simpler handling are also available in which the test elements are, for example, stored in a cartridge in the analysis equipment and provided for measurement. A further step in miniaturization can be achieved, for example, by integrating several functions or functional elements in a single analytic auxiliary means (disposable). By suitably combining a piercing process and sensory analyte concentration detection on a test element, the operation can, for example, be drastically simplified.
U.S. Publication No. 2006/0155317 discloses a lancet device for generating puncture wounds in a skin surface, which device comprises an integrated test element in the form of a reference element with a lancet and a sample take-up unit. The test element is firstly fixedly coupled onto a coupling mechanism of the lancet device. In a first position of the coupling mechanism, the lancet of the test element is actuated using a coupling rod and a connecting rod, and a piercing movement is carried out. Subsequently, the entire coupling mechanism with the test element fixedly coupled thereto is moved into a second position by a pivot movement, in which second position an opening of a sample take-up channel of the test element is situated over the puncture site for taking up a liquid sample.
Publication No. WO 2005/107596 discloses a multiplicity of spaced apart lancets on a tape. According to one embodiment, the tape not only carries the lancets, but also a multiplicity of test elements, each of which is assigned to one of the lancets. Therefore, this is a tape with a multiplicity of analytic auxiliary means which are arranged in a spaced apart fashion and allow integration of piercing procedures and sample take-up procedures in one sampling system.
The overall size plays a prominent role in integrated measurement systems. An object of integrated systems has to be that of providing equipment which is not much larger than the conventional non-integrated systems. One approach in this direction consists of using combination drives in which a motion sequence takes over a number of functions. By way of example, Publication No. WO 2006/013045 discloses a system in which an electrically operated motor firstly provides energy for a mechanical energy store and also operates an additional system function, either at the same time or independently therefrom. By way of example, this system function can be a cartridge transport or a test element transport. In order to use the motor at subsequent times for different functions, a transmission and/or a coupling is proposed which actively couples the motor to or again decouples the motor from the corresponding system function which is desired at the time. Various coupling systems are proposed.
The device proposed in Publication No. WO 2006/013045 therefore represents a substantial step toward a higher degree of integration. However, not all options for integration have been exhausted in this case because, even in the system proposed in Publication No. WO 2006/013045, there are still additional system functions which generally have to be supplied with energy by separate drives. Furthermore, the active coupling elements proposed in Publication No. WO 2006/013045 for coupling the drive to different system functions are technically complex and, in certain circumstances, susceptible to faults.